1. Technical Field of the Invention
The invention relates to a system for the detection of the wear state of machine parts which are subject to mechanical wear, by means of an electronic transmitting/receiving device and at least one transponder device which is embedded in the machine part and sends back an acknowledgement signal in response to a transmitted signal which is transmitted by the transmitting/receiving device.
2. Description of the Prior Art
Many technical fields relating to heavy machine construction make use of machine parts which are subject to the influence of large forces during operation, and are thus continuously subject to high wear. By way of example, in the field of waste separation and reprocessing and mining machines, large feed or processing apparatuses such as drills or worm feeds are used, which are subject to relatively rapid wear, in which case the wear state and/or the reaching of a wear limit must be indicated reliably in order that the worn machine part can be replaced in good time.
DE 102 27 677 discloses a method for wire-free monitoring of the state of a machine part that is subject to wear by means of transponders, with an electrical conductor track structure being proposed which is worn together with the machine part, and with this conductor track structure being connected to a transponder and sending a response signal as a function of the state of the conductor track structure. This arrangement is not suitable for use for machine parts subject to major mechanical wear.
DE 198 40 081 discloses a system for monitoring the wear state of a layer, in which a transponder is provided underneath the layer and an electromagnetically shielding layer is embedded in the layer that is subject to wear and prevents signals from being interchanged between the transmitting/receiving device and the transponder, so that a signal interchange such as this is possible after the destruction of this layer, and this indicates the destruction state.
One disadvantage of this system is that the failure of the transponder before the destruction of the shielding layer is not indicated, because this does not receive and cannot transmit any signal, with the possible consequence that, in a situation such as this, the detection device assumes that the layer is still intact with the shielding layer embedded in it, while the layer has possibly already been totally destroyed.